Water filter unit



FIG. 1 is a perspective view taken from the top, front and right side of a water filter unit showing my new design;

FIG. 2 is a left side elevational view thereof;

FIG. 3 is a perspective view taken from the bottom, front and left side thereof;

FIG. 4 is a rear elevational view thereof; and

FIG. 5 is a top plan view thereof. 

The ornamental design for a water filter unit, substantially as shown. 